The vast majority of medical care remains focused on late stage illness, a bias that perpetuates the health care crisis in the U.S. and internationally. It is estimated that seventy-five percent of national health care costs in the U.S relate to the treatment of chronic diseases [1, 2]. Heart failure, for example, affects 5 million people and costs approximately $21 billion annually in the U.S. [3]. Although not classified as a chronic condition, Alzheimer's disease takes a similar toll: it now affects 4.5 million Americans, and is estimated to cost the U.S. $100 billion annually [4, 5]. To a large extent, the diseases that we treat almost exclusively in their late stages progress predictably, as do the costs of treatment. Symptoms that are difficult and costly to treat in late stages can be stabilized and sometimes reversed if addressed early. A growing body of literature suggests common vulnerabilities for heart failure, dementia, and a range of other diseases. These shared risk factors—negative affectivity, isolation, and weight gain—are ideal targets for preventive medicine.

Shifting more attention and resources to preventive care could certainly increase return on medical investment. But there are significant barriers: the close monitoring of risk factors required for preventive medicine is difficult for both clinicians and individuals. Clinicians lack sensitive tools to determine individual baselines of premorbid functioning and early signs of decline. Among individuals facing the prospect of a daunting disease, psychological dynamics such as denial and adaptive optimism delay acknowledgement of symptoms. People frequently overlook early signs and avoid clinical assessment, but at the same time eagerly adopt strategies to prevent future disease and compensate for their current limitations [6].

Figure 1: Embedded Assessment: Closing the loop. This approach links health monitoring with tailored feedback to help individuals compensate for current limitations and prevent disease.

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Embedded assessment emerged as a design resolution to the conflict between the need for early detection and significant obstacles to health monitoring. In this approach, continuous assessment is integrated into an individual's routines and translated into supportive, tailored feedback. The feedback helps the person compensate for current limitations and prevent future disease. The closed loop between monitoring and compensation ensures that individuals receive the appropriate level of support. Conversely, trending of users' responses to graduated cues reveals variability in how much help is required at different times—data that can help with early detection. If embedded assessment technologies are adopted in midlife for performance optimization and disease prevention, they can identify individual baselines and early indicators of health decline (see Figures 1 and 2 and [6]).

Figure 2: Opportunities for early detection. Diagnosis and treatment are delayed by limitations in clinical assessment and psychological dynamics such as denial. Embedded assessment determines personal baselines and early disease indicators.

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In this paper I examine three means for embedded assessment to assist with management and prevention of disease. I review three research prototypes that vary in preventive reach (from acute symptom management to risk reduction far in advance of illness), the time intervals for monitoring, and the degree to which monitored data are translated into feedback. The first, a mobile oximetry device, is intended to reduce acute risks associated with exercise in heart-failure patients. It monitors cardiovascular exertion levels over short time intervals and reflects them in a relatively straightforward manner. The second, a social health platform for older adults, monitors and facilitates behaviors with preventive value over slightly longer intervals (from days to months versus minutes). The feedback is translated from a quantitative index of social interactions into metaphorical visualizations of interpersonal engagement. The last, a mobile feedback system for emotional self-regulation and preventive cardiology, is the most far reaching of these projects. It is intended to be used far in advance of disease onset, and it translates physiological data into psychological interventions.